/**
 * Copyright The Apache Software Foundation
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package com.alibaba.wasp.metrics;

/**
 * BaseSource for dynamic metrics to announce to Metrics2.
 */
public interface BaseSource {

  public static final String WASP_METRICS_SYSTEM_NAME = "Wasp";

  /**
   * Clear out the metrics and re-prepare the source.
   */
  void init();

  /**
   * Set a gauge to a specific value.
   * 
   * @param gaugeName the name of the gauge
   * @param value the value
   */
  void setGauge(String gaugeName, long value);

  /**
   * Add some amount to a gauge.
   * 
   * @param gaugeName the name of the gauge
   * @param delta the amount to change the gauge by.
   */
  void incGauge(String gaugeName, long delta);

  /**
   * Subtract some amount from a gauge.
   * 
   * @param gaugeName the name of the gauge
   * @param delta the amount to change the gauge by.
   */
  void decGauge(String gaugeName, long delta);

  /**
   * Remove a metric and no longer announce it.
   * 
   * @param key Name of the gauge to remove.
   */
  void removeMetric(String key);

  /**
   * Add some amount to a counter.
   * 
   * @param counterName the name of the counter
   * @param delta the amount to change the counter by.
   */
  void incCounters(String counterName, long delta);

  /**
   * Add some value to a histogram.
   * 
   * @param name the name of the histogram
   * @param value the value to add to the histogram
   */
  void updateHistogram(String name, long value);

  /**
   * Add some value to a Quantile (An accurate histogram).
   * 
   * @param name the name of the quantile
   * @param value the value to add to the quantile
   */
  void updateQuantile(String name, long value);

  /**
   * Get the metrics context. For hadoop metrics2 system this is usually an all
   * lowercased string. eg. fserver, master
   * 
   * @return The string context used to register this source to hadoop's
   *         metrics2 system.
   */
  String getMetricsContext();

  /**
   * Get the description of what this source exposes.
   */
  String getMetricsDescription();

  /**
   * Get the name of the context in JMX that this source will be exposed
   * through. This is in ObjectName format. With the default context being
   * Hadoop -> Wasp
   */
  String getMetricsJmxContext();

  /**
   * Get the name of the metrics that are being exported by this source. Eg.
   * IPC, GC, WAL
   */
  String getMetricsName();
}
